1. Field of the Invention
This invention relates to a unitary bifurcated tubing and an extrusion apparatus for making the same.
2. Prior Art
Bifurcated or "Y" tubing is well known in the art and has many applications. For example, "Y" tubing is commonly found on medical devices such as stethoscopes, drain tubing, intravenous sets, vacuum manifolds and the like. Bifurcated tubing is presently made by one of two processes. The first process involves the use of a "Y" or "T" adapter (usually plastic) which is a (usually molded) article having three tubular arms projecting from a common axis each arm having an inner lumen; each inner lumen being fluidly connected to the inner lumen of the other arms. Means are provided on the distal or terminal end of each of the three "Y" adapter arms for the attachment of tubing to provide a bifurcated tubing assembly. Thus, although the goal of dividing a single tube having a single lumen into two tubes having separate lumens is achieved, the assembly has three structurally weak points where each of the three separate tubes are attached to the arms of the "Y" adapter. The assembled non-unitary bifurcated tubing is vulnerable to separation at these points. Product failure due to separation of a "Y" tube is particularly dangerous when the "Y" or bifurcated tubing is intended to be employed in a medical application such as the intravenous administration of two or more fluid medicaments wherein such separation may result in loss of life.
Molding is another method employed for making bifurcated tubing. Molding has the advantage that it produces a "Y" tubing having unitary construction. The problem with molding is that length of the tubing comprising the "arms" of the "Y" tubing is practically limited by the physical size of the mold in which the "Y" tubing is being produced. Thus, it is not possible to mold a bifurcated tubing having a unitary structure which is not constrained to a particular length by the size of the mold. For certain applications such as distributing or collecting a fluid or tube-transmissible information to and/or from a plurality of locations such size constraints imposed by molding the "Y" tubing may preclude using a unitary bifurcated tubing.
Due to the joint separation problems discussed earlier and wherein a "Y" tube assembly and imposed thereon by connecting separate tubes to a "Y" type adapter, and the limitation due to the practiced restriction on tube length inherent in the molding method of making a "Y" tube, it is desirable to employ extrusion to produce a unitary "Y" tubing which resists separation and can be made in any length.